Self Administration Transaction - Additional Information (Detail)
 3 Months Ended 12 Months Ended
Oct. 19, 2021
$ / shares
Mar. 24, 2021
shares
Jun. 28, 2019
USD ($)
$ / shares
shares
Mar. 31, 2020
USD ($)
Dec. 31, 2021
USD ($)
$ / shares
Dec. 31, 2020
USD ($)
Dec. 31, 2019
USD ($)
Nov. 10, 2020
Business Acquisition [Line Items]                
Earnout unit exchange per share | $ / shares $ 10.66   $ 10.66   $ 10.66      
Estimated fair value of consideration transferred     $ 111,300,000          
Gain resulting from acquisition of unconsolidated affiliates           $ 0 $ 8,017,353  
Conversion of partnership units on achievement of first tier of earnout consideration | shares   1,121,795            
Goodwill impairment charges         $ 0 36,465,732 0  
Estimated fair value of contingent earnout liability           $ 23.9 $ 31.1  
Investment impairment charges       $ 4.4        
Percentage of joint venture assets   100.00%            
Incremental assets under management         $ 472      
Agreement term     3 years          
Administrative services agreement renewal term         no later than 90 days      
Minority and Marketability Discount                
Business Acquisition [Line Items]                
Alternative investment, measurement input               0.06
Contribution Agreement                
Business Acquisition [Line Items]                
Percentage of fair value of equity interests     50.00%          
Gain resulting from acquisition of unconsolidated affiliates     $ 8.0          
Class A-2 Units | Class A-2 Units Converted to Class A-1 Units | SS OP Holdings                
Business Acquisition [Line Items]                
Number of limited partnership units | shares   1,094,434            
Conversion of partnership units on achievement of first tier of earnout consideration | shares   1,121,795            
Contribution Agreement | SmartStop Asset Management                
Business Acquisition [Line Items]                
Percentage of voting membership interest     100.00%          
Number of on-site self storage employees     350          
Cash     $ 769,126          
Debt assumption     $ 15,000,000          
Contribution Agreement | Class A-1 Units | SmartStop Asset Management                
Business Acquisition [Line Items]                
Number of limited partnership units | shares     8,698,956          
Contribution Agreement | Class A-2 Units | SmartStop Asset Management                
Business Acquisition [Line Items]                
Number of limited partnership units | shares     3,283,302          
Operating Partnership Agreement                
Business Acquisition [Line Items]                
Number of limited partnership units | shares     20,000          
Cash received     $ 200,000          
Operating Partnership Agreement | Class A Common stock                
Business Acquisition [Line Items]                
Earnout unit exchange per share | $ / shares         $ 10.66      
Operating Partnership Agreement | Class A-1 Units                
Business Acquisition [Line Items]                
Lock-up expiration date         Jun. 28, 2021      
Conversion of stock, description         The Class A-1 Units are subject to the general restrictions on transfer contained in the Operating Partnership Agreement. In addition, through June 28, 2021 (the “Lock-Up Expiration”), the Class A-1 Units could not be sold, pledged, or otherwise transferred or encumbered except in certain limited circumstances set forth in the Contribution Agreement. The Class A-1 Units were and are now otherwise entitled to all rights and duties of the Class A limited partnership units in the Operating Partnership, including cash distributions and the allocation of any profits or losses in the Operating Partnership. The Class A-2 Units may convert into Class A-1 Units as earnout consideration, as described below. The Class A-2 Units are not entitled to cash distributions or the allocation of any profits or losses in the Operating Partnership until the Class A-2 Units are converted into Class A-1 Units.      
Operating Partnership Agreement | Class A-2 Units                
Business Acquisition [Line Items]                
Class of unit expiration year         7 years      
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature A                
Business Acquisition [Line Items]                
Class of unit conversion percentage         33.33%      
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature A | Minimum                
Business Acquisition [Line Items]                
Incremental AUM under operating partnership     300,000,000          
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature B                
Business Acquisition [Line Items]                
Class of unit conversion percentage         33.33%      
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature B | Minimum                
Business Acquisition [Line Items]                
Incremental AUM under operating partnership     500,000,000          
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature C                
Business Acquisition [Line Items]                
Class of unit conversion percentage         33033.00%      
Operating Partnership Agreement | Class A-2 Units | Unit Conversion Feature C | Minimum                
Business Acquisition [Line Items]                
Incremental AUM under operating partnership     $ 700,000,000          
Operating Partnership Agreement | Class A-2 Units | Class A-2 Units Converted to Class A-1 Units | SS OP Holdings                
Business Acquisition [Line Items]                
Number of limited partnership units | shares   1,094,434            
Self Administration Transaction                
Business Acquisition [Line Items]                
Impairment charges       11,700,000        
Self Administration Transaction | Trademarks                
Business Acquisition [Line Items]                
Impairment charges       3,300,000        
Self Administration Transaction | Management Contracts of SST IV                
Business Acquisition [Line Items]                
Impairment charges       2.2        
Self Administration Transaction | Management Contracts of SSGTII                
Business Acquisition [Line Items]                
Impairment charges       6.2        
Self Administration Transaction | Managed REIT Platform                
Business Acquisition [Line Items]                
Goodwill impairment charges       24.7        
Deferred tax liabilities       $ 2.4        
Amendment to Operating Partnership Agreement                
Business Acquisition [Line Items]                
Estimated fair value of contingent earnout liability         $ 30.0